Harcourt Park - Wellington Fault Line - Garden of Isengard

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If you like the idea of having a picnic or a barbecue on top of a major earthquake fault, Harcourt Park in Upper Hutt is a good place to go. It’s a lovely spot to visit on a summer day. It has lots of old-established trees, grassy open spaces, shrubberies, a playground for the kids, an outdoor theatre space where summer entertainments may be mounted. And it straddles the Wellington earthquake fault. Of course, the Wellington fault doesn’t move very often – about once in every 500 to 700 years. It could be as much as 200 years from now before the next move.

And when it happens, the movement could be somewhere else along its 400-or-so kilometre length. So you’d be fairly safe to settle somewhere in the park and open up your picnic hamper – most of the time. It makes you think, though. Much of New Zealand is earthquake-prone and the Wellington region is probably the most vulnerable. At least four major faults cut through the region. However, it is this sleeping giant – the Wellington fault-line - that passes through the heart of Wellington city, under houses, schools, and offices, under lifelines such as motorways, water reservoirs and pipes, electricity systems, sewerage pipes, gas pipes, and telecommunication lines. Wellington city illustrates the problems of planning urban development along faults.

The Wellington Fault can be traced over 420 kilometres.

Beginning in Cook Strait; it cuts the coastline between Sinclair Head and Tongue Point, runs north-east to the Karori Reservoirs, then along Tinakori Hill, under a part of the Prime Minister’s residence, and then offshore in Wellington Harbour beneath the ferry terminal and parallel to the Old Hutt Road, leading on to the Western Hutt Motorway in the Hutt Valley. A good vantage point from which to view the broader plate boundary environment of Wellington and the Hutt Valley is Mount Victoria, in the city.

The Wellington Fault scarp shows clearly as the northwestern margin of the harbour, while the Lower Hutt Valley, in the distance, forms a wedge-shaped area between the scarp and the eastern hills. Incidentally, the Thorndon overbridge, an important transport link into and out of Wellington city, crosses over the Wellington fault. It’s built on reclaimed land along the harbour edge and was completed in 1969. Since then, however, the over- bridge has been strengthened so that it meets today’s seismic design codes. It even has brackets between the bridge sections, allowing them to move individually. Another large infrastructure work, the Haywards Substation in the western Hutt Valley is also well protected. Much of the complex equipment in this major electric power junction is mounted on base isolators to mitigate any damage from shaking. As well, many spare parts are kept on hand, including a spare giant transformer. Base isolators are a New Zealand invention and you can find out more about them and see some at the Museum of New Zealand, Te Papa.

Further out in the Hutt Valley, the Wellington Fault veers away from the motorway, heading through the suburb of Totara Park, before heading over a low saddle at Brown Owl and on into the Tararua Ranges and onward to the Manawatu River. In Totara Park, a clear view of the fault scarp can be seen as it leaves California Drive and passes through California Park at the north-east end of the suburb. A footbridge crosses the Hutt River from California Park to Harcourt Park and it’s in this area that the effects of earthquake faulting in past centuries can best be seen. Harcourt Park is where this true short story began. If you’re having a picnic there, be sure to look around you for signs of the times when the Wellington Fault moved.

The Lord of the Rings set for the 'Garden of Isengard' is also in Harcourt Park, and a short walk to the Birchville Dam and the longer Cannon Point Walkway are close by.

WELLINGTON LORD OF THE RINGS TOUR

Image Credits: Benjamin Allcock